Forming reliable contacts on tight semiconductor pitch
A method of forming a semiconductor device includes forming a trench in a passivating layer between neighboring fins. A barrier is formed in the trench. Conductive contacts are formed in the passivating layer to provide electrical connectivity to the fins. The conductive contacts are in direct contact with sidewalls of the barrier. A semiconductor device includes a passivating layer over a pair of fins. A barrier extends through the passivating layer and between the pair of fins and that electrically isolates the fins. Electrical contacts are formed through the passivating layer to the fins. The electrical contacts directly contact sidewalls of the barrier.
Latest IBM Patents:
Technical Field
The present invention relates to forming semiconductor devices with small device pitch and, more particularly, to forming a liner between contacts.
Description of the Related Art
As the size of transistors and other semiconductor devices decreases, these devices may be packed with ever greater efficiency onto integrated chips. In addition, improved fabrication technologies allow these devices to be formed closer together than ever before.
However, as the pitch between semiconductor devices decreases and the individual components of the devices come closer together, the risk of fabrication errors increases. In addition, the fabrication of some components may be coarse relative to others. In one example, forming contacts to the gates and source and drain regions of transistors can be difficult on tight semiconductor pitches, as a larger top critical dimension is used. This may result in contacts that are large enough to contact neighboring devices, creating short circuits that may lead to device failure.
The ground rules of the integrated chip design therefore need the contacts to be separated to prevent tip-to-tip or tip-to-side shorts, limiting the reduction in the area consumed by the device that would otherwise be possible with improved fabrication technologies.
SUMMARYA method for forming semiconductor devices includes forming a trench in a passivating layer between neighboring fins. A barrier is formed in the trench. Conductive contacts are formed in the passivating layer to provide electrical connectivity to the fins. The conductive contacts are in direct contact with sidewalls of the barrier.
A method for forming semiconductor devices includes forming a raised source and drain layer directly on a plurality of neighboring fins. A passivating layer is formed directly over the raised source and drain layer. A trench is formed that extends through the passivating layer and the raised source and drain layer between neighboring fins. A barrier is formed in the trench. Conductive contacts are formed in the passivating layer to provide electrical connectivity to the fins, wherein the conductive contacts are in direct contact with sidewalls of the barrier.
A semiconductor device includes a passivating layer over a pair of fins. A barrier extends through the passivating layer and between the pair of fins and that electrically isolates the fins. Electrical contacts are formed through the passivating layer to the fins. The electrical contacts directly contact sidewalls of the barrier.
These and other features and advantages will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings.
The disclosure will provide details in the following description of preferred embodiments with reference to the following figures wherein:
Embodiments of the present invention prevent short circuits between adjacent device contacts by providing a robust liner between devices. The liner may be formed with the width of a single fin pitch shallow-trench isolation (STI) to provide isolation between the neighboring devices.
Referring now to the drawings in which like numerals represent the same or similar elements and initially to
A passivating layer 108 is formed over the raised source and drain regions 108. The passivating layer 108 may be formed from any appropriate insulating material, including for example silicon dioxide. Two contacts 116 are shown, one for each of the respective fins 110. The contacts are separated by a barrier formed from a liner 112 and a flowable insulator 114. The flowable insulator 114 may be formed as, e.g., a chemical vapor deposition of silicon dioxide. The liner 112 may be formed from, e.g., a dielectric such as hafnium dioxide or silicon nitride. The barrier prevents the contacts 116 from coming into contact with one another as a result of process variations, such that the contacts 116 may be placed closer together. This in turn means that the fins 110 can be placed closer together, such that the overall pitch between devices is decreased.
Illustrative examples of silicon-containing materials suitable for the bulk-semiconductor substrate 100 include, but are not limited to, silicon, silicon germanium, silicon germanium carbide, silicon carbide, polysilicon (i.e., polySi), epitaxial silicon (i.e., epi-Si), amorphous silicon (i.e., α:Si), and multi-layers thereof. Although silicon is the predominantly used semiconductor material in wafer fabrication, alternative semiconductor materials can be employed, such as, but not limited to, germanium, gallium arsenide, gallium nitride, silicon germanium, cadmium telluride and zinc selenide. Although not depicted in
The semiconductor layer 102 and fins 110 may be formed from any appropriate semiconductor material including, e.g., type IV and type III-V semiconductors. The term “type III-V compound semiconductor” denotes a semiconductor material that includes at least one element from Group III of the Periodic Table of Elements and at least one element from Group V of the Periodic Table of Elements. Typically, the III-V compound semiconductors are binary, ternary or quaternary alloys including III/V elements. Examples of III-V compound semiconductors that can be used in the present invention include, but are not limited to alloys of gallium arsenic (GaAs), aluminum arsenic (AlAs), indium gallium arsenic (InGaAs), indium aluminum arsenic (InAlAs), indium aluminum arsenic antimony (InAlAsSb), indium aluminum arsenic phosphorus (InAlAsP), indium gallium arsenic phosphorus (InGaAsP) and combinations thereof.
It is to be understood that the present invention will be described in terms of a given illustrative architecture having a wafer; however, other architectures, structures, substrate materials and process features and steps may be varied within the scope of the present invention.
It will also be understood that when an element such as a layer, region or substrate is referred to as being “on” or “over” another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” or “directly over” another element, there are no intervening elements present. It will also be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present.
A design for an integrated circuit chip may be created in a graphical computer programming language, and stored in a computer storage medium (such as a disk, tape, physical hard drive, or virtual hard drive such as in a storage access network). If the designer does not fabricate chips or the photolithographic masks used to fabricate chips, the designer may transmit the resulting design by physical means (e.g., by providing a copy of the storage medium storing the design) or electronically (e.g., through the Internet) to such entities, directly or indirectly. The stored design is then converted into the appropriate format (e.g., GDSII) for the fabrication of photolithographic masks, which typically include multiple copies of the chip design in question that are to be formed on a wafer. The photolithographic masks are utilized to define areas of the wafer (and/or the layers thereon) to be etched or otherwise processed.
Methods as described herein may be used in the fabrication of integrated circuit chips. The resulting integrated circuit chips can be distributed by the fabricator in raw wafer form (that is, as a single wafer that has multiple unpackaged chips), as a bare die, or in a packaged form. In the latter case the chip is mounted in a single chip package (such as a plastic carrier, with leads that are affixed to a motherboard or other higher level carrier) or in a multichip package (such as a ceramic carrier that has either or both surface interconnections or buried interconnections). In any case the chip is then integrated with other chips, discrete circuit elements, and/or other signal processing devices as part of either (a) an intermediate product, such as a motherboard, or (b) an end product. The end product can be any product that includes integrated circuit chips, ranging from toys and other low-end applications to advanced computer products having a display, a keyboard or other input device, and a central processor.
Reference in the specification to “one embodiment” or “an embodiment” of the present principles, as well as other variations thereof, means that a particular feature, structure, characteristic, and so forth described in connection with the embodiment is included in at least one embodiment of the present principles. Thus, the appearances of the phrase “in one embodiment” or “in an embodiment”, as well any other variations, appearing in various places throughout the specification are not necessarily all referring to the same embodiment.
It is to be appreciated that the use of any of the following “/”, “and/or”, and “at least one of”, for example, in the cases of “A/B”, “A and/or B” and “at least one of A and B”, is intended to encompass the selection of the first listed option (A) only, or the selection of the second listed option (B) only, or the selection of both options (A and B). As a further example, in the cases of “A, B, and/or C” and “at least one of A, B, and C”, such phrasing is intended to encompass the selection of the first listed option (A) only, or the selection of the second listed option (B) only, or the selection of the third listed option (C) only, or the selection of the first and the second listed options (A and B) only, or the selection of the first and third listed options (A and C) only, or the selection of the second and third listed options (B and C) only, or the selection of all three options (A and B and C). This may be extended, as readily apparent by one of ordinary skill in this and related arts, for as many items listed.
Referring now to
Shown on
Referring now to
Referring now to
Referring now to
Referring now to
Referring now to
Referring now to
Referring now to
Referring now to
Block 1008 deposits a passivating layer 108 on the raised source/drain layer 108. The passivating layer 108 may be deposited by any appropriate deposition technique, as described above, and then planarized to a specified thickness. Block 1010 forms trenches 904 between the fins, creating isolation that extends down to the level of the dielectric material 104. Block 1012 forms the barrier in the trenches 904, creating the dielectric liner 112 and the dielectric barrier 114. Block 1014 etches the passivating layer 108 to expose areas of the raised source and drain regions located over the fins 110. Block 1016 forms the contacts 116, optionally forming a silicide-like metal infiltration layer on the raised source and drain regions 106 to facilitate electrical connection between the fins 110 and the contacts 116.
Having described preferred embodiments of semiconductor devices on tight semiconductor pitches and methods of forming the same (which are intended to be illustrative and not limiting), it is noted that modifications and variations can be made by persons skilled in the art in light of the above teachings. It is therefore to be understood that changes may be made in the particular embodiments disclosed which are within the scope of the invention as outlined by the appended claims. Having thus described aspects of the invention, with the details and particularity required by the patent laws, what is claimed and desired protected by Letters Patent is set forth in the appended claims.
Claims
1. A method for forming semiconductor devices, comprising:
- forming a trench in a passivating layer between neighboring fins;
- forming a barrier in the trench; and
- forming conductive contacts in the passivating layer to provide electrical connectivity to the fins, wherein the conductive contacts are in direct contact with sidewalls of the barrier.
2. The method of claim 1, further comprising forming a raised source and drain layer directly on the neighboring fins.
3. The method of claim 2, wherein forming the trench further comprises forming the trench in the raised source and drain layer, separating the raised source and drain layer into respective raised source and drain regions for the respective fins.
4. The method of claim 2, further comprising etching the passivating layer in a region over the fins with an etch that does not affect the barrier to form contact trenches, wherein the conductive contacts are formed in the contact trenches.
5. The method of claim 2, wherein forming the raised source and drain layer comprises forming the raised source and drain layer at a height that exceeds a height of the fins.
6. The method of claim 5, wherein the conductive contacts are formed directly on the raised source and drain layer.
7. The method of claim 2, further comprising forming a gate structure on each of the neighboring fins.
8. The method of claim 1, wherein forming the barrier comprises:
- forming a liner dielectric along sidewalls of the trench; and
- forming filling the remaining trench with a barrier dielectric.
9. The method of claim 8, wherein forming the liner dielectric comprises:
- depositing a uniform layer of dielectric material over the all sides of the trench; and
- anisotropically etching the layer of dielectric material to remove material on horizontal surfaces.
10. A method for forming semiconductor devices, comprising:
- forming a raised source and drain layer directly on a plurality of neighboring fins;
- forming a passivating layer directly over the raised source and drain layer;
- forming a trench that extends through the passivating layer and the raised source and drain layer between neighboring fins;
- forming a barrier in the trench; and
- forming conductive contacts in the passivating layer to provide electrical connectivity to the fins, wherein the conductive contacts are in direct contact with sidewalls of the barrier.
11. The method of claim 10, further comprising etching the passivating layer in a region over the fins with an etch that does not affect the barrier to form contact trenches, wherein the conductive contacts are formed in the contact trenches.
12. The method of claim 10, wherein forming the raised source and drain layer comprises forming the raised source and drain layer at a height that exceeds a height of the fins.
13. The method of claim 12, wherein the conductive contacts are formed directly on the raised source and drain layer.
14. The method of claim 10, wherein forming the barrier comprises:
- forming a liner dielectric along sidewalls of the trench; and
- forming filling the remaining trench with a barrier dielectric.
15. The method of claim 14, wherein forming the liner dielectric comprises:
- depositing a uniform layer of dielectric material over the all sides of the trench; and
- anisotropically etching the layer of dielectric material to remove material on horizontal surfaces.
7405116 | July 29, 2008 | Carter et al. |
8362568 | January 29, 2013 | Lin et al. |
8377759 | February 19, 2013 | Cheng et al. |
8765599 | July 1, 2014 | Yuan et al. |
8809184 | August 19, 2014 | Yuan et al. |
8890260 | November 18, 2014 | Chuang et al. |
8921191 | December 30, 2014 | Cai et al. |
8946793 | February 3, 2015 | Xie et al. |
8975712 | March 10, 2015 | Rashed et al. |
8981493 | March 17, 2015 | Cheng et al. |
20110127589 | June 2, 2011 | Chen et al. |
20120001263 | January 5, 2012 | Richter et al. |
20120256238 | October 11, 2012 | Ning |
20140167162 | June 19, 2014 | He et al. |
20150060960 | March 5, 2015 | Xie et al. |
20150061015 | March 5, 2015 | He et al. |
20150069527 | March 12, 2015 | Kerber et al. |
20150069531 | March 12, 2015 | Naczas et al. |
20150069532 | March 12, 2015 | Xie et al. |
20150279975 | October 1, 2015 | Hsiao |
20150303295 | October 22, 2015 | Wan |
20160049394 | February 18, 2016 | Shin |
20160049516 | February 18, 2016 | Huang |
20160254370 | September 1, 2016 | Kelly |
- Basker, V.S. et al.,, “A 0.063 μm2 FinFET SRAM cell demonstration with conventional lithography using a novel integration scheme with aggressively scaled fin and gate pitch,” 2010 Symposium on VLSI Technology, Jun. 2010. (pp. 19-20).
- Guillorn, M. et al., “FinFET Performance Advantage at 22nm: An AC perspective,” 2008 Symposium on VLSI Technology, Jun. 2008. (pp. 12-13).
Type: Grant
Filed: Sep 9, 2015
Date of Patent: Feb 7, 2017
Assignees: INTERNATIONAL BUSINESS MACHINES CORPORATION (Armonk, NY), GLOBALFOUNDRIES INC (Cayman Islands)
Inventors: Xiuyu Cai (Niskayuna, NY), Kangguo Cheng (Schenectady, NY), Ali Khakifirooz (Los Altos, CA), Ruilong Xie (Niskayuna, NY), Tenko Yamashita (Schenectady, NY)
Primary Examiner: Asok K Sarkar
Application Number: 14/849,269
International Classification: H01L 21/768 (20060101); H01L 29/78 (20060101); H01L 29/66 (20060101); H01L 29/08 (20060101);